Course at the CHR summer school 2013: Abduction and language processing with CHR

Abduction refers to the sort reasoning that infers facts by means of which a given
observation can be explained. This can be understood as reasoning backwards from
an observed effect to its possible cause, e.g., from symptoms to diagnosis.
Abduction is often accompanied by so-called integrity constraints that limit
the inferred facts or causes to be what is believed to conform with some possible world.

CHR allows an elegant encoding of abduction, by mapping abducible facts into CHR
constraints and integrity constraints into CHR rules.
Combining this with Prolog as a general knowledge representation system yields an
easy-to-use and powerful environment for abductive reasoning. When, furthermore,
this is combined with Prolog's grammar notation, DCGs, we obtain a system abductive language interpretation.

CHR Grammars represent another system in which CHR rules are applied for bottom-up analysis,
which can also be combined with abduction in CHR as described.

Finally, we show a recent adaptation of CHR with persistent constraint stores, shared between
different software agent. This system is intended for the knowledge intensive components in
interactive installation, but seems also to be relevant for a wider class of applications.

Slides

Find pdf version here (Keynote version for Mac available from the author.)
Please notice copyright; write to author if any doubt.